We are testing the efficacy of short-term substitution of a surrogate opiate (LAAM) for heroin, followed by naltrexone to aid in maintaining abstinence. Follow-up will be at one and two years following termination of treatment. In the course of this study various ancillary data are being obtained, such as detailed information about LAAM safety and toxicity, experience with rapid induction onto LAAM, experience with naloxone testing for heroin dependence, comparison of fast and slow withdrawal from LAAM, experience with a new method of monitoring the validity of urine samples, and experience in developing tools for effective education of patients about naltrexone.